The invention relates to phenolic resin polyols and their preparation by oxyalkylation. The phenolic resin polyols of the invention have aliphatic or mixed aliphatic/phenolic hydroxyl groups, which makes them versatile intermediates for a broad range of polymer systems, including urethanes, epoxies, alkyds, acrylates, and polyesters.
A new class of phenol aralkylation polymers was recently described. These polymers exhibit improved oil solubility, improved compatibility with oil and alkyd-based polymers, urethanes, and epoxies, and a decreased tendency to form color bodies that darken coatings derived from the phenol aralkylation polymers. One way to make the phenol aralkylation polymers is to first aralkylate a phenolic monomer (such as bisphenol A) with a styrene derivative to obtain an aralkylated phenol, and then react the aralkylated phenol with an aryl diolefin to produce the phenol aralkylation polymer. This reaction scheme is illustrated in the simplified scheme below: 
As those skilled in the art will appreciate, these polymers are actually complex mixtures that contain many structural analogs of the compounds pictured above. The types of structures actually present, of course, depend greatly upon the relative proportions of phenolic monomer, styrene derivative, and aryl diolefin.
Phenol aralkylation polymers can be made by first reacting the phenolic monomer with an aryl diolefin to obtain a phenovaryl diolefin polymer, and then aralkylating the phenol/aryl diolefin polymer with a styrene derivative to obtain a phenol aralkylation polymer. In this case, the phenolic component is joined to the aryl diolefin with at least a portion of the phenolic linkages para to the phenolic hydroxyl groups. This process, which produces a phenol aralkylation polymer having a higher melting point, is shown in the simplified scheme below: 
The phenol aralkylation polymers described above have many advantages compared with standard phenolics, including good solubility, good compatibility, and low discoloration. Improved solubility in nonpolar solvents is a direct consequence of styrene component addition, as is the improved compatibility with other typical resin systems, including epoxies, acrylates, styrenics, and the like. Lower rates of discoloration compared with phenolics result from the absence of dihydromethylene linkages.
The usefulness of phenol aralkylation polymers, however, is somewhat limited by the presence of only phenolic hydroxyl groups. For example, the usefulness of phenol aralkylation polymers in the coating and adhesive product areas is limited by the inability of phenolic hydroxyl groups to react either with organic acids to form esters, or with esters to form new esters by transesterification. The esterification and transesterification reactions require aliphatic hydroxyl groups. In addition, phenol aralkylation polymers having only phenolic hydroxyl groups will not react with maleic anhydride to produce unsaturated polyesters. In sum, although the limited reactivity of phenol aralkylation polymers does not preclude their use in coatings and adhesives, it does restrict their usefulness in these applications.
The invention is a phenolic resin polyol. The phenolic resin polyol is the reaction product of an aralkylated phenol or a phenol aralkylation polymer with an oxyalkylating agent selected from alkylene oxides and alkylene carbonates. Unlike either the aralkylated phenol or phenol aralkylation polymer, the phenolic resin polyol contains at least some aliphatic hydroxyl groups.
The invention includes a process for making phenolic resin polyols. The process comprises reacting an aralkylated phenol or a phenol aralkylation polymer with an oxyalkylating agent selected from alkylene oxides and alkylene carbonates in the presence of an oxyalkylation catalyst under conditions effective to produce the phenolic resin polyol.
Reaction with an alkylene carbonate adds a single oxyalkylene unit, and effectively converts a phenolic hydroxyl group to an aliphatic hydroxyl group. When an alkylene oxide is used, multiple oxyalkylene units can be added. This allows the solubility and compatibility characteristics of the phenolic resin polyols to be adjusted for a particular end use. With either type of oxyalkylating agent, the relative proportion of phenolic and aliphatic hydroxyl groups can be adjusted easily, so a formulator has great flexibility and control over polyol reactivity.
The phenolic resin polyols are exceptionally useful in preparing a wide variety of polymer systems. Like phenol aralkylation polymers, they react, for example, with melamine resins to produce melamine-linked polymers, with di- or polyisocyanates or isocyanate-terminated prepolymers to make polyurethanes, or with epoxy resins to make epoxy thermosets. Unlike phenol aralkylation polymers, the phenolic resin polyols of the invention also react with diacids or polyacids to make polyesters, with fatty acids or fatty esters to make alkyds, and with acrylic acids or esters to make curable acrylate compositions. In sum, we found that incorporation of aliphatic hydroxyl groups into these phenolic polymers expands their usefulness in polymer systems, yet still maintains the advantages of phenol aralkylation polymers in many systems.
The phenolic resin polyols of the invention are the reaction products of an aralkylated phenol or a phenol aralkylation polymer with an oxyalkylating agent selected from alkylene oxides and alkylene carbonates.
xe2x80x9cAralkylated phenolsxe2x80x9d useful in the invention are made by aralkylating a phenolic monomer with at least one styrene derivative. A typical reaction is shown below: 
xe2x80x9cPhenol aralkylation polymersxe2x80x9d useful in the invention derive from a phenolic monomer, at least one styrene derivative, and a coupling agent, which is typically an aryl diolefin. Mixtures of different phenolic monomers, styrene derivatives, or coupling agents can be used to modify physical properties.
Phenol aralkylation polymers are produced by a process that has at least two steps. The reaction sequence is controlled to provide phenol aralkylation polymers that have the desired properties. In one process, a phenolic monomer reacts with at least one styrene derivative to produce an aralkylated phenol. The aralkylated phenol then reacts with a coupling agent, preferably an aryl diolefin, to produce the phenol aralkylation polymer. A second process reacts the phenolic monomer first with the coupling agent, and then with the styrene derivative to produce the phenol aralkylation polymer. Both of these processes are illustrated in the Background section. In either process, part of the styrene derivative or coupling agent can be withheld for later reaction to modify performance characteristics of the phenol aralkylation polymer.
The aralkylated phenols or phenol aralkylation polymers described above react with an oxyalkylating agent selected from alkylene oxides and alkylene carbonates in the presence of an oxyalkylation catalyst under conditions effective to produce phenolic resin polyols of the invention.
Phenolic monomers useful in the invention include phenols that have at least two free xe2x80x9creactivexe2x80x9d positions, i.e., two aromatic Cxe2x80x94H bonds that are activated for electrophilic aromatic substitution. In other words, the phenolic monomers have at least two aromatic Cxe2x80x94H groups in positions either ortho or para to a phenolic hydroxyl group. Phenol, for example, has three free reactive positions: two ortho and one para to the phenolic hydroxyl group.
The phenols may be substituted with one or more C1-C20 alkyl, aryl, or aralkyl substituents, provided that at least two reactive positions remain. Suitable substituted phenols include, for example, o-cresol, m-cresol, p-cresol, m-isopropyl phenol, 3,5-xylenol, 3,5-diisopropylphenol, p-t-butylphenol, and the like, and mixtures thereof. Suitable phenols include those having more than one phenolic hydroxyl group, such as hydroquinone, resorcinol, catechol, and C1-C20 alkyl, aryl, and aralkyl-substituted derivatives of these phenols, provided again that the phenolic monomer has at least two activated aromatic Cxe2x80x94H bonds. Examples include 2-ethylresorcinol, 4-methylresorcinol, 5-ethyl-resorcinol, 3-methylcatechol, 4-methylcatechol, 2,3-dimethylhydroquinone, 2,5-diethylhydroquinone, 2,6-dimethylhydroquinone, 3,4-dimethylcatechol, 3,5-diethylcatechol, and the like, and mixtures thereof. For any of the alkyl, aryl, or aralkyl-substituted phenolic monomers, the substituent or substituents may derive from aralkylation of a phenol with a styrene derivative.
Suitable phenolic monomers also include alkyl, aryl, and aralkyl-substituted polyhydroxy-polycyclic aromatic phenols such as substituted dihydroxynaphthalenes, dihydroxyanthracenes, and dihydroxyphenanthrenes. Also included are polynuclear phenolic monomers, such as bisphenol A, bisphenol F, dihydroxy-biphenyl bisphenols (including those prepared by the Mead Process; see U.S. Pat. No. 4,900,671, which is incorporated herein by reference), and coupling products derived from phenols and aldehydes or ketones. Preferred phenolic monomers, because of their low cost and availability, are phenol, bisphenol A, bisphenol F, hydroquinone, resorcinol, catechol, p-t-butyl phenol, p-cumyl phenol, and p-octyl phenol.
Styrene derivatives useful in the invention are aryl-substituted alkenes. Examples include styrene, xcex1-methylstyrene, xcex2-methylstyrene, o-, m-, and p-methylstyrenes, xcex1-methyl-p-methylstyrene, vinyltoluenes, t-butylstyrenes, ethylstyrenes, di-t-butylstyrenes, isopropenylnaphthalenes, 2-methyl-1,1-diphenyl-1-propene, 1-phenyl-1-pentene, and the like, and mixtures thereof. Styrene derivatives include aryl-substituted alkenes in which the aryl group is, for example, phenyl (as in styrene), naphthyl, biphenyl, and alkyl-, aryl-, aralkyl-, or halogen-substituted derivatives of phenyl, naphthyl, and biphenyl. The styrene derivatives can include other functional groups such as carboxylic acids (e.g., cinnamic acid) or esters (e.g., methyl cinnamate). Such functionalized styrene derivatives provide a valuable way to introduce carboxyl functionality into the phenolic resin polyols. Preferred styrene derivatives are styrene, xcex1-methylstyrene, vinyltoluenes, t-butylstyrenes, ethylstyrenes, di-t-butylstyrenes, and mixtures thereof.
Coupling agents useful in the invention are compounds that can join activated aromatic rings of phenolic monomers together by two electrophilic addition reactions. Preferred coupling agents are aryl diolefins and aldehydes. Aryl diolefins are generally preferred because they improve the solubility of the phenolic resin polyols in mineral spirits and avoid potential formaldehyde emission issues. Aldehydes offer a low-cost alternative to the diaryl olefins. Suitable aldehydes include, for example, formaldehyde, acetaldehyde, benzaldehyde, glyoxal, and the like, and mixtures thereof. Formaldehyde is particularly preferred.
Aryl diolefins useful in the invention have at least one aromatic ring and two polymerizable carbon-carbon double bonds, which may or may not be attached to the same aromatic ring. The olefin groups can be substituted with one or more C1-C5 alkyl groups. The aromatic ring moiety can be, for example, benzene, naphthalene, biphenyl, or the like. The aromatic ring or rings can be substituted with one or more C1-C5 alkyl groups.
Suitable aryl diolefins include, for example, divinylbenzenes, diiso-propenylbenzenes, divinylnaphthalenes, divinylbiphenyls, isopropenylstyrenes, diisopropenylnaphthalenes, diisopropenylbiphenyls, and the like, and mixtures thereof. Preferred aryl diolefins are divinylbenzenes and diisopropenylbenzenes, which are commercially available. One preferred and commercially available mixture of divinylbenzenes contains 80% divinylbenzenes (m- and p-isomers) and 20% ethylstyrenes. Diisopropenylbenzenes are also preferred.
The aryl diolefins can be produced in situ, if desired, by dehydrating the corresponding diol precursors, usually at elevated temperatures under acidic conditions. For example, diisopropenylbenzenes can be produced from the corresponding methylbenzylic alcohols. When a diol precursor is used, it is typically added to the phenolic monomer incrementally under conditions effective to allow simultaneous removal of water as the olefin is generated by dehydration.
The relative amounts of phenolic monomer, styrene derivative, and coupling agent (diaryl olefin or aldehyde) used depend on many factors, including the type of aralkylated phenol or phenol aralkylation polymer desired, the desired product molecular weight, the desired hydroxyl functionality, and so on. Generally, the mole ratio of coupling agent to phenolic monomer used is within the range of about 0.2 to about 1.1, more preferably from about 0.4 to about 0.8. The amount of styrene derivative used depends mainly on the desired degree of styrenation, and is limited by the number of free reactive aromatic Cxe2x80x94H sites on the phenolic monomer. Generally, from about 20% to about 100%, preferably from about 40% to about 95% of the sites available for styrenation will be used. The average hydroxyl functionality of the aralkylated phenol or phenol aralkylation polymer is preferably within the range of about 2 to about 10, and more preferably from about 2 to about 8.
A catalyst is generally used in the aralkylation processes used to make the aralkylated phenol or phenol aralkylation polymer. Typically, an acid catalyst is used. Suitable acid catalysts include alkylsulfonic acids, arylsulfonic acids, phenol sulfonic acids, sulfonated phenolic polymers, fixed-bed catalysts such as sulionated polystyrene, sulfuric acid, phosphoric acid, hydrochloric acid, phosphate mono- and diesters, latent acid catalyst systems (acid chlorides, phosphorous oxychlorides, amine salts), halogenated organic acids (chloroacetic, trifluoroacetic acid), and organic acids having a pKa less than about 1.5. As those skilled in the art will appreciate, the amount of acid catalyst needed depends on many factors, including the effective acidity and type of catalyst selected. The amount used can vary over a wide range; preferably, the amount of acid catalyst used is within the range of about 0.001 to about 5 wt. % based on the total weight of the monomers used. Strong acids such as the alkyl- and arylsulfonic acids are preferably used in an amount less than about 0.2 wt. %, while weaker acids such as fixed-bed catalysts may require significantly higher levels.
Although any suitable temperature can be used for the aralkylation reactions, a temperature within the range of about 120xc2x0 C. to about 180xc2x0 C. is preferred. Ordinarily, the temperature is adjusted to permit completion of the reaction within a desired amount of time. After aralkylation is complete, the product is generally neutralized with an alkali metal hydroxide, tertiary amine, or other alkaline material. The alkaline material is often then conveniently used as an oxyalkylation catalyst for the next step.
The phenolic resin polyols of the invention are made by reacting an aralkylated phenol or a phenol aralkylation polymer with an oxyalkylating agent selected from the group consisting of alkylene oxides and alkylene carbonates.
Alkylene oxides contain an epoxide group. Suitable alkylene oxides are epoxides in which one or both of the epoxide carbons is substituted with hydrogen or a C1-C10 alkyl, aryl, or aralkyl group. Preferred alkylene oxides are C2-C4 epoxides, including ethylene oxide, propylene oxide, isobutylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. Alkylene oxides that contain halogenated alkyl groups, such as epihalohydrins, can also be used. Propylene oxide, ethylene oxide, and isobutylene oxide are particularly preferred.
Alkylene carbonates are cyclic carbonates that contain xe2x80x94Cxe2x80x94CO2xe2x80x94 in a five-membered ring. Suitable alkylene carbonates are cyclic carbonates in which one or both of the aliphatic ring carbons is substituted with hydrogen or a C1-C10 alkyl, aryl, or aralkyl group. Preferred alkylene carbonates are ethylene carbonate, propylene carbonate, and butylene carbonates.
The invention includes a process for making phenolic resin polyols. This process involves oxyalkylation of an aralkylated phenol or a phenol aralkylation polymer with an alkylene carbonate or an alkylene oxide. The process generally requires an oxyalkylation catalyst; a catalyst can be omitted, but reaction times are long, and high temperatures are needed. Generally, the aralkylated phenol or phenol aralkylation polymer is heated with the alkylene carbonate or alkylene oxide in the presence of the oxyalkylation catalyst under conditions effective to produce the phenolic resin polyol.
Suitable oxyalkylation catalysts include alkali metals; alkali metal and alkaline earth metal alkoxides, hydroxides, hydrides, carbonates, bicarbonates, oxides, sulfonates, amides, acetonylacetates, carboxylates, and phenolates; tertiary amines; alkylammonium halides, hydroxides, alkoxides, bicarbonates, and carbonates; Lewis acids (e.g., boron trifluoride, aluminum chloride, tin tetrachloride); inorganic acids (e.g., HCl, H2SO4); carboxylic acids; sulfonic acids; metalloporphrins; dialkylzinc compounds; and double metal cyanide compounds. Other catalysts useful for oxyalkylation appear in K. J. Ivin and T. Saegusa, Ring-Opening Polymerization, Vol. 1 (Elsevier) 1984, Chapter 4, xe2x80x9cCyclic Ethers.xe2x80x9d Additional examples are found in U.S. Pat. Nos. 3,393,243, 4,595,743, and 5,106,874, the teachings of which are incorporated herein by reference.
The amount of catalyst needed in any case depends on the type of catalyst used, the particular catalyst chosen, the reaction conditions used, the nature of the aralkylated phenol or aralkylation polymer, and other factors. Generally, the amount of catalyst needed will be within the range of about 1 ppm to about 5 wt. % based on the amount of phenolic resin polyol. Those skilled in the art will understand how to adjust the amount of catalyst used based on these factors to permit an efficient synthesis of the phenolic resin polyols.
The relative amounts of alkylene carbonate or alkylene oxide used depend on the desired product. When an alkylene carbonate is used as the oxyalkylating agent, a maximum of one oxyalkylene unit is added to the aralkylated phenol or phenol aralkylation polymer per phenolic hydroxyl group, even if an excess amount of alkylene carbonate is used. If a phenolic resin polyol containing both phenolic and aliphatic hydroxyls is desired, then the alkylene carbonate can be added in amount sufficient to cap only some of the phenolic hydroxyl groups. The ability to make phenolic resin polyols that have both phenolic and aliphatic hydroxyl groups is an advantage of the invention because the reactivity of these polyols can be fine-tuned to suit a particular end-use application.
When an alkylene oxide is used as the oxyalkylating agent, one or more oxyalkylene units can be added to each of the phenolic hydroxyl groups of the aralkylated phenol or phenol aralkylation polymer. As with alkylene carbonates, alkylene oxides can be added in amount sufficient to cap only some of the phenolic hydroxyl groups. Unlike alkylene carbonates, alkylene oxides allow addition of multiple oxyalkylene units to the phenolic hydroxyl groups. This feature permits the preparation of a wide variety of products that differ in the degree of alkoxylation. A large number of oxyalkylene units may be desirable for many purposes, for example: introducing flexibility into coatings, modifying solubility characteristics of the polyols, or reducing viscosity.
The oxyalkylation may be performed at any desired temperature. Generally, the oxyalkylation occurs at a temperature within the range of about 20xc2x0 C. to about 250xc2x0 C., but the required temperature depends significantly on the type of catalyst used. For example, oxyalkylation using propylene carbonate and potassium hydroxide as a catalyst is conveniently performed at temperatures in the 100xc2x0 C. to 250xc2x0 C. range, and more preferably in the 140xc2x0 C. to 210xc2x0 C. range. In contrast, propoxylation with propylene oxide using some Lewis acid catalysts can be performed at room temperature.
The rate of oxyalkylation can be greatly enhanced, particularly in the case of viscous reaction products, when a vacuum is applied during this step. Reaction times can be reduced by 100% or more simply by reducing the pressure in the reactor. Preferably, the vacuum applied will be sufficient to assist removal of carbon dioxide from the viscous polymer mixture, but will not strip unreacted propylene carbonate from the mixture. A reactor pressure of about 0.3 to about 0.6 atmospheres is preferred for oxyalkylation.
After the oxyalkylation reaction is complete, insoluble salts or catalysts can be removed, if desired by any convenient method. In one method, the phenolic resin polyol is simply diluted with mineral spirits and is filtered using a filter aid (e.g. CELITE filter aids, or the like). Vacuum stripping of the mineral spirits gives a purified phenolic resin polyol.
The phenolic resin polyols of the invention are exceptionally useful in preparing a wide variety of polymer systems. Like phenol aralkylation polymers, they react with melamine resins to produce melamine-linked polymers. Suitable melamine resins include commercial grade hexamethoxymethylmelamines such as, for example, CYMEL 303 crosslinking agent, a product of American Cyanamid Company. Example 19 below illustrates the preparation of a melamine coating from a phenolic resin polyol of the invention.
A polyurethane composition is made by reacting a phenolic resin polyol of the invention with a di- or polyisocyanate or an isocyanate-terminated prepolymer. Prepolymers derived from the phenolic resin polyols can be used. Optionally, a low molecular weight chain extender (diol, diamine, or the like) is included. Suitable di- or polyisocyanates are those well known in the polyurethane industry, and include, for example, toluene diisocyanates (TDIs), methylene diphenylene diisocyanate (MDI), polymeric MDIs, carbodiimide-modified MDIs, hydrogenated MDIs, isophorone diisocyanate, and the like. Isocyanate-terminated prepolymers can be made in the usual way from a polyisocyanate and a polyether polyol, polyester polyol, or the like. The polyurethane is formulated at any desired NCO index, but it is preferred to use an NCO index close to 1. If desired, all of the available NCO groups are reacted with hydroxyl groups from the phenolic resin polyols and any chain extenders. Alternatively, an excess of NCO groups remain in the product, as in a moisture-cured polyurethane. Many types of polyurethane products can be made, including, for example, adhesives, sealants, coatings, and elastomers. Example 5 below shows how to make a urethane coating from a phenolic resin polyol of the invention.
The invention includes epoxy thermosets made by reacting a phenolic resin polyol of the invention with an epoxy resin. Suitable epoxy resins generally have two or more epoxy groups available for reaction with the hydroxyl groups of the phenolic resin polyol. Particularly preferred epoxy resins are bisphenol-A diglycidyl ether and the like. Examples 15 and 17 below show how to make epoxy coatings of the invention from phenolic resin polyols. Other suitable methods for making epoxy thermosets are described in U.S. Pat. No. 4,609,717, the teachings of which are incorporated herein by reference. In addition, epoxies can be formed by reacting the phenolic resin polyols of the invention with epoxy resins in the presence of an imidazole catalyst such as 2-phenyl imidazole.
Polyesters of the invention are reaction products of the phenolic resin polyols with an anhydride, a dicarboxylic acid, or polycarboxylic acid. Suitable anhydrides and carboxylic acids are those commonly used in the polyester industry, and include, for example, phthalic anhydride, phthalic acid, maleic anhydride, maleic acid, adipic acid, isophthalic acid, terephthalic acid, sebacic acid, succinic acid, trimellitic anhydride, and the like, and mixtures thereof. Example 15 shows how a polyester made from a phenolic resin polyol and trimellitic anhydride can be used in an epoxy coating. Other suitable methods for making polyesters are described in U.S. Pat. No. 3,457,324, the teachings of which are incorporated herein by reference.
The invention includes alkyds made from the phenolic resin polyols. In one method, the phenolic resin polyol is combined with a fatty acid and optionally a low molecular weight polyol and/or an anhydride, to produce the alkyd. In another method, a fatty acid ester reacts with the phenolic resin polyol and, optionally, an anhydride to produce the alkyd. Suitable fatty acids and fatty acid esters for making the alkyds are those generally known in the alkyd resin art, and include, for example, oleic acid, ricinoleic acid, linoleic acid, licanic acid, and the like, and mixtures thereof, and their mono-, di-, and triglyceryl esters. Tung oil is a particularly preferred fatty ester. Mixtures of saturated and unsaturated fatty acids and esters can be used. Alkyds of the invention are particularly useful for making alkyd coatings. Typically, the resin is combined with an organic solvent, and the resin solution is stored until needed. A drying agent such as cobalt acetate is added to the solution of alkyd resin, the solution is spread onto a surface, the solvent evaporates, and the resin cures leaving an alkyd coating of the invention. Examples 6 and 7 show how to make alkyd coatings from phenolic resin polyols of the invention. Other suitable methods for making alkyd resins and coatings are described in U.S. Pat. No. 3,423,341, the teachings of which are incorporated herein by reference.
The invention includes polyurethane-modified alkyds (uralkyds) prepared from the phenolic resin polyols. These resins are valuable for making uralkyd coatings. As those skilled in the art will appreciate, there are many ways to make uralkyds. One way is to react a phenolic resin polyol with a fatty acid, a low molecular weight polyol, a di- or polyisocyanate, and optionally, an anhydride, to produce a uralkyd. A second method reacts the phenolic resin polyol with a fatty acid ester, a di- or polyisocyanate, and optionally, an anhydride, to produce the uralkyd. Examples 8, 9, 10, 12, and 13 illustrate the versatility of phenolic resin polyols in several uralkyd formulations. Additional methods for making uralkyds are described in U.S. Pat. No. 3,267,058, the teachings of which are incorporated herein by reference.
Curable acrylate compositions of the invention are prepared by reacting the phenolic resin polyols with an acrylic or methacrylic acid or ester. Esterification of the polyol hydroxyl group gives a polymer having ethylenic unsaturation that can be crosslinked to produce a cured acrylate composition. Example 18 shows how to make an acrylate/urethane coating from a phenolic resin polyol of the invention using acrylic acid and 1,6-hexanediol diacrylate.
The phenolic resin polyols have many advantages over other phenolic polymers. Unlike the aralkylated phenols and phenol aralkylation polymers, they react with diacids or polyacids to make polyesters, with fatty acids or fatty esters to make alkyds, and with acrylic acids or esters to make curable acrylate compositions. Thus, incorporation of aliphatic hydroxyl groups into these phenolic polymers expands their usefulness in polymer systems, especially coating applications. The ability to make phenolic resin polyols that have any desired proportion of phenolic and aliphatic hydroxyl groups allows the reactivity of these polyols to be adjusted to suit a particular end-use application. Finally, the ability to incorporate multiple oxyalkylene units into the structure of the phenolic resin polyols using alkylene oxides allows formulators to introduce flexibility into coatings, modify solubility characteristics of the polyols, or reduce viscosity.